Center shifted roll forming

ABSTRACT

The present invention provides a bending machine for strip, webbing, or rod material comprising: an electronic control means; two cylinders, each acting selectively as a forming mandrel or a forming tool; an angular displacement means, controlling the orbit of the forming mandrel; and a feeding means, controlling the rate of material advancement; wherein a curvilinear profile of varying radii is formed in at least a portion of a material by varying the feed rate and the angular displacement, individually or in conjunction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part of application Ser. No. 10/896,257, filed Jul. 21, 2004, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates generally to an improved roll forming mechanism. And, more particularly, this invention relates to the forming of malleable materials, such as tubes, strips, sheets, webbing, and similar materials into a curvilinear profile, using a roll form machine known to industry, wherein two parallel cylinders selectively act as both a forming mandrel and a forming tool.

As designs in numerous industries become more organic and irregular, having non-repeating patterns and complex shapes (designed to increase strength, increase beauty, maximize performance, or provide clearance), devices are required to form these complex shapes and underlying frameworks. Industries employing these complex design profiles include the aerospace, construction, process industries, and many others.

Current roll form devices, utilizing parallel cylinders, tend to focus on forming repeating or regular patterns in the material, wherein the forming mandrel diameter determines primarily the diameter of the corrugation pattern and the bend angle being primarily determined by the angular displacement of the forming tool around the forming mandrel. These devices are limited in the shapes that can be produced. More complex shapes required in modern industry are not possible with current roll forming means

For instance, in the aerospace industry, it is common to utilize I-beam like structural members having a curvilinear web extending normally between a top and bottom flange. The generally curvilinear profile of the web provides increased strength to weight performance, improved stiffness, and decreased volume. Additionally, in order to accommodate the aircraft wiring harness, hydraulic and fuel lines, as well as immediate strength and volume requirements, the geometry of the web may greatly vary in profile from one point to another down the beam, creating a potentially non-repeating, complex web corrugation pattern.

Currently, structural members are generally constructed from metal or composite materials. With either choice of material, the construction of a structural member with a curvilinear web is a challenge, in maintaining quality, tolerances, and minimizing costs. With the high cost of manufacturing composite structural members, due to the labor intensive techniques utilized, it is often more economical and practical to use metals, such as titanium and aluminum, to construct curvilinear structural members, when the design allows for it.

What is needed is a device that can quickly and economically produce complex curvilinear patterns in malleable materials, especially in metals. What is further needed is a device that can produce a bending radius that is approximately equal to or greater than the forming mandrel. What is additionally needed is a device that can be programmed to bend a complex series of radii or planar sections along a material.

SUMMARY OF THE INVENTION

In accordance of the present invention, a roll forming machine capable of quickly and economically producing complex curvilinear patterns in malleable materials is provided. The present invention further provides a device that can produce a bending radius that is approximately equal to or greater than the forming mandrel. The present invention again further provides a device that can be programmed to bend a complex series of radii or planar sections along a material.

The present invention provides a bending machine for strip, webbing, or rod material comprising:

-   -   an electronic control means, the electronic control means         storing and executing a set of instructions, the set of         instructions directing a material feed rate, the set of         instructions also directing an angular displacement;     -   a first cylinder; and a second cylinder, the second cylinder         positioned parallel to the first cylinder, the first cylinder         and the second cylinder each acting selectively as a forming         mandrel or a forming tool, the forming mandrel being held         stationary, the forming tool revolving about the forming mandrel         with the angular displacement;     -   an angular displacement means, the angular displacement means         being coupled with the forming tool and the forming mandrel, the         angular displacement means variably affecting the angular         displacement of the selected forming tool continuously, the         angular displacement means being responsive to the electronic         control means;     -   a feeding means, the feeding means variably controlling the feed         rate of the material continuously, the feeding means being         responsive to the electronic control means;     -   wherein a curvilinear profile of a varying radii is formed in at         least a portion of the material by varying the feed rate and the         angular displacement, from zero to a maximum, each formed radius         of the curvilinear profile being equal to or greater than a         forming mandrel radius.

The present invention can form complex curvilinear profiles in materials by adjusting the feed rate of the material and the angular displacement of the forming tool. For example, if a formed radius that is larger than the forming mandrel is required, the angular displacement can be held constant while the material is advanced. Or, if a complex curve (second, third, or nth order equation) is required, the feed rate and the angular displacement can be adjusted simultaneously. For a small radius with a sharp bend angle, it may be necessary to slow the feed rate while increasing the angular displacement. Along the length of the material, the radius and bend angle can be varied, the present invention transitioning easily from one portion of a complex curve to another. Many complex shapes are possible with the present invention, through controlled variations in material feed rate and angular displacement.

Numerous common designs for the roll form machine utilizing the selectively alternating cylinders are well known in industry and need not be described further in detail, the particular mechanism being shown in the proceeding description being for illustrative purposes only. The unique combination and usage of the components of the present invention provide the unexpected and unique result of a complex curvilinear profile in a formed material, with varying radii and bending angles.

The angular displacement means can be any number of mechanisms that serve to selectively hold the forming mandrel stationary while rotating the forming tool in an orbit around the forming mandrel. For instance, the angular displacement means can be a mechanical device such as a geared mechanism, a pneumatic device, an actuated device, or a similar mechanism. The exact mechanism to affect the degree of orbit of the selected forming tool is not central to the present invention, and is compatible with any such mechanism that can receive a command from the electronic control means of the present invention and adjust the angular displacement accordingly. The angular displacement, sector of the orbit over which the forming tool is rotated, can be held at any degree between zero and the maximum degree of orbit. Additionally, the angular displacement can be continuously adjusted throughout the forming process, to create varying bend angles and radii.

The electronic control means can be any device (such as a computing means or similar) that can store a set of instructions, then communicate a signal, correlating to those instructions, to the angular displacement means and the feeding means, the set of instructions determining the feed rate of the material and the angular displacement of the forming tool. The set of instructions are developed to create a series of radii in a material. This set of instructions can be entered into the computing means manually by an operator; or the set of instructions can be imported from a CAD/CAM system, wherein a solid model or other compatible technology is translated into the afore mentioned set of instructions.

The feeding means can be any number of devices known to industry and designed to advance a material into the bending machine, such as a roller mechanism. The present invention is compatible with any feeding mechanism that can receive a command from the electronic control means of the present invention and adjust the feed rate accordingly.

The present invention can operate in several modes, depending on the shape being formed, the properties of the material be formed, or other design demands. The angular displacement and the feed rate can be varied simultaneously; the angular displacement can be held constant and the feed rate varied; and the angular displacement can be varied and the feed rate held constant. Through a combination of these modes, complex formed shapes can be achieved.

Additionally, the roll form machine of the present invention can be used in conjunction with an inspection means. Upon completion of the roll form process, the formed section of the material can be inspected with known inspection techniques. If the curvilinear shape is found to be out of compliance or approaching this limit, adjustments can be made to the forming process, either manually or automatically (through proportional control or similar), to correct the error.

A method for the manufacture of curvilinear profile strip, webbing, or rod material using a bending machine of the present invention is provided comprising the steps of:

-   -   a) receiving a set of instructions from an electronic control         means, the electronic control means storing and executing the         set of instructions, the set of instructions commanding an         angular displacement for each instant and a feed rate for each         instant of the bending process;     -   b) inserting the material between a first cylinder and a second         cylinder being in parallel orientation, the first cylinder and         the second cylinder each acting selectively as a forming mandrel         or a forming tool, the forming mandrel being held stationary,         the forming tool be capable of revolving about the forming         mandrel at the angular displacement; and     -   c) advancing the material at the feed rate and revolving the         forming mandrel at the angular displacement.

In the case of the manufacture of a titanium webbing for application in aerospace, the design of the webbing is created, taking into account the strength requirements of the structural member and interferences with nearby structures and components. The final webbing design, in this exemplified case, is a complex series of curves of varying radii and planar sections, forming a curvilinear profile. This complex curvilinear profile can be created accurately by the roll form device of the present invention.

For each radius defined in the design, there is a corresponding material feed rate and angular displacement of the forming tool. The angular displacement of the forming tool can vary from zero to a maximum; and the feed rate can vary continuously from a reverse maximum to a forward maximum. This feed rate and angular displacement data can be entered into the electronic control means as a set of instructions, such as a computer, CNC device, or the like. The set of instructions consists of an instantaneous feed rate (the feed rate required at each point along the length of the webbing) and an instantaneous angular displacement (the angular displacement required at each point along the length of the webbing) correlating to each said radius of the curvilinear profile. The electronic control means produces a signal or series of signals correlating to the set of instructions, received in turn by the feeding means and angular displacement means, the feeding means altering feed rate according to instructions and the angular displacement means altering the angular displacement according to instructions.

A sheet of titanium material is fed into the roll form machine, being advanced by the feeding means and inserted between the forming mandrel and the forming tool. Several options are available to create a complex webbing profile, depending on the instant radius, the instant bend angle, and how the instant bend transitions to and from contiguous bends, the instant bend being defined as the bend presently being formed.

The first option is to maintain a constant feed rate while varying the angle. In other words, the forming tool is transitioning from one angular position to another, in rotation about the forming mandrel, while the material is being advanced forward at a constant feed rate. One resultant shape of this method could be a curvilinear profile whose curvature varies along the material.

A second option is to vary the feed rate and vary the angle simultaneously. Again, in other words, the forming tool is transitioning from one angular position to another, in rotation about the forming mandrel, while the material is being advanced forward at a varying feed rate. This might be required if a sharp bend angle is specified in the design, the feed rate possible slowing or coming to a stop while the forming tool rotates about the forming mandrel, to produce the sharp bend angle in the material. Of course, the present invention is capable of combining the preceding options to create a complex series of bends along the webbing

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of the present invention.

FIG. 2 c-c is a top view of a material formed by the present invention and forming tool positions required to create the formed profile.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The detailed description set forth below in connection with the appended drawings is intended as a description of presently-preferred embodiments of the invention and is not intended to represent the only forms in which the present invention may be constructed and/or utilized. The description sets forth the functions and the sequence of steps for constructing and operating the invention in connection with the illustrated embodiments. However, it is to be understood that the same or equivalent functions and sequences may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention.

Looking at FIG. 1, the mechanical setup of a roll form machine (20) that is compatible with the preferred embodiment of the present invention is shown. The first cylinder (22) and the second cylinder (24) are in a home position, where neither are selected as the forming tool, and both are in the hoe position with zero angular displacement. The angular displacement means (28), shown in phantom, is mechanically coupled with the first cylinder (22) and the second cylinder (24), having the capability of selectively orbiting one cylinder about the other, one cylinder being the stationary forming mandrel and the other cylinder being the orbiting forming tool. The angular displacement means (28) is in data communications with the electronic control means (26) through data line (40). A signal correlating to a set of instructions can be transmitted, digital, analog, or similar, through data line (40), instructing the angular displacement means (28) to hold the selected forming mandrel stationary, while orbiting the forming tool through an angular displacement at an angular velocity. Both the angular displacement and angular velocity can be varied continuously from a minimum to a maximum, the angular displacement generally ranging, but not limited to, between zero and a maximum, the angular velocity having both clockwise and counterclockwise capabilities.

The feeding means (30) controls the rate at which the material (36) is fed into the roll form machine (20), the feeding rollers (34) gripping the material (36) from both sides and advancing the material (36) towards the material inlet (32). The feeding means (30) is in data communications with the electronic control means (26) through data line (38). A signal correlating to a set of instructions can be transmitted, digital, analog, or similar, through data line (38), instructing the feeding means (30) to advance or retract the material (36) at a feed rate. The feeding means (30) can additionally be any number of devices that are capable of advancing and retracting the material (36) at a feed rate.

Looking more particularly at FIG. 2 a, the profile of a formed sheet (44) with a curvilinear profile can be seen. This shown profile is just one of number that can be formed by the roll form machine (20) of the present invention. The profile is irregular and non-repeating in the formed sheet (44) with varying radii and bend angles. For example bend (46) has a large radius and a relatively small bend angle, while bend (52) has a small radius and a relatively large bend angle. In order to manufacture the formed sheet (44) a machine must have the capabilities of forming widely differing radii and bend angles without unduly slowing or stopping the material or changing the forming mandrel. The present invention can create all of the bends shown (46-56) without the need to change either the bending mandrel or the bending tool, while creating a smooth transition from one curve to another.

As can be seen in FIG. 2 b-c, a large radius bend is being formed, exemplary of bends (46), (48), (50), (54), and (56). A bend with a large radius, starting with bend (46), is achieved by rotating the forming tool, the second cylinder (24) in this case, over an angular displacement Δθ₁, and holding that angular displacement while advancing the material (36) at a given feed rate, forming a curve to the left. Subsequent curve (48) can be formed by deselecting the second cylinder (24) as the forming tool and, in turn, selecting the first cylinder (22) as the new forming tool, while advancing the material (36) at a given feed rate, being either constant or varying in speed, to form a curve to the right. Moving on to the forming of bend (50), again the second cylinder (24) is selected as the forming tool and the first cylinder (22) is selected as the forming mandrel, while advancing the material (36) at a given feed rate, being either constant or varying in speed, to form a curve to the left.

When forming bend (52) thereafter, it is likely necessary to slow the feed rate in order to form the small radius and large bend angle. The configuration of the roll form machine (20) to achieve bend (52) can be seen in FIG. 2 c. The angular displacement Δθ₂ is larger than with previously described bending operations. After bend (52) has been formed, bend (54) can be formed. While transitioning from bend (52) to bend (54) is might be necessary to adjust both the feed rate and the angular displacement simultaneously to create a smooth transition between the bends.

Many complex bending profiles with varying radii, bend angles, and bend directions are easily formed by the present invention, through careful control by computer of the angular displacement means (28) and the feeding means (30), with a preprogrammed schedule of bends being commanded from the set of instructions stored on the computer.

While the present invention has been described with regards to particular embodiments, it is recognized that additional variations of the present invention may be devised without departing from the inventive concept. 

1) A bending machine for strip, webbing, or rod material comprising: an electronic control means, said electronic control means storing and executing a set of instructions, said set of instructions directing a material feed rate, said set of instructions directing an angular displacement; a first cylinder; a second cylinder, said second cylinder positioned parallel to said first cylinder, said first cylinder and said second cylinder each acting selectively as a forming mandrel or a forming tool, said forming mandrel being held stationary, said forming tool revolving about said forming mandrel with said angular displacement; an angular displacement means, said angular displacement means being coupled with said forming tool and said forming mandrel, said angular displacement means variably affecting said angular displacement of said forming tool continuously, said angular displacement means being responsive to said electronic control means; a feeding means, said feeding means variably affecting said feed rate of said material continuously, said feeding means being responsive to said electronic control means; wherein a curvilinear profile of a varying radii is formed in at least a portion of said material by varying said feed rate and said angular displacement, each said radius of said curvilinear profile being equal to or greater than said forming mandrel radius. 2) The bending machine of claim 1 wherein said electronic control means is a computer, said set of instructions being entered and stored on said computer, said set of instructions consisting of an instantaneous feed rate and an instantaneous angular displacement correlating to each said radius of said curvilinear profile. 3) The bending machine of claim 1 wherein said angular displacement and said feed rate are varied simultaneously. 4) The bending machine of claim 1 wherein said angular displacement is held constant and said feed rate is varied. 5) The bending machine of claim 1 wherein said angular displacement is varied and said feed rate is held constant. 6) A method for the manufacture of curvilinear profile strip, webbing, or rod material using a bending machine of the present invention comprising the steps of: a) receiving a set of instructions from an electronic control means, said electronic control means storing and executing said set of instructions, said set of instructions commanding an angular displacement and a feed rate; b) inserting said material between a first cylinder and a second cylinder being in parallel orientation, said first cylinder and said second cylinder each acting selectively as a forming mandrel or a forming tool, said forming mandrel being held stationary, said forming tool revolving about said forming mandrel at said angular displacement; c) advancing said material at said feed rate and, simultaneously, revolving said forming mandrel at said angular displacement. 7) A method for the manufacture of curvilinear strip, webbing, or rod material using a bending machine of the present invention comprising the steps of: b) feeding a material into said bending machine at a feed rate, said material being inserted between a first cylinder and a second cylinder being in parallel orientation, said first cylinder and said second cylinder each acting selectively as a forming mandrel or a forming tool, said forming mandrel being held stationary, said forming tool revolving about said forming mandrel at an angular displacement; c) revolving said forming mandrel to a specified angular displacement, said angular displacement determining a radius of a curve; d) holding the forming mandrel at said angular displacement; e) advancing said material at said feed rate. 